﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Daramkun.Liqueur.Exceptions;
using Daramkun.Liqueur.IO.Compression.Utilities;

namespace Daramkun.Liqueur.IO.Compression.Algorithms
{
	sealed class InflateBlocks
	{
		private const int MANY = 1440;

		internal static readonly int [] border = new int [] { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };

		private enum InflateBlockMode
		{
			TYPE = 0,
			LENS = 1,
			STORED = 2,
			TABLE = 3,
			BTREE = 4,
			DTREE = 5,
			CODES = 6,
			DRY = 7,
			DONE = 8,
			BAD = 9,
		}

		private InflateBlockMode mode;

		internal int left;

		internal int table;
		internal int index;
		internal int [] blens;
		internal int [] bb = new int [ 1 ];
		internal int [] tb = new int [ 1 ];

		internal InflateCodes codes = new InflateCodes ();

		internal int last;

		internal ZlibCodec _codec;

		internal int bitk;
		internal int bitb;
		internal int [] hufts;
		internal byte [] window;
		internal int end;
		internal int readAt;
		internal int writeAt;
		internal System.Object checkfn;
		internal uint check;

		internal InfTree inftree = new InfTree ();

		internal InflateBlocks ( ZlibCodec codec, System.Object checkfn, int w )
		{
			_codec = codec;
			hufts = new int [ MANY * 3 ];
			window = new byte [ w ];
			end = w;
			this.checkfn = checkfn;
			mode = InflateBlockMode.TYPE;
			Reset ();
		}

		internal uint Reset ()
		{
			uint oldCheck = check;
			mode = InflateBlockMode.TYPE;
			bitk = 0;
			bitb = 0;
			readAt = writeAt = 0;

			if ( checkfn != null )
				_codec.adler32 = check = Adler.Adler32 ( 0, null, 0, 0 );
			return oldCheck;
		}


		internal int Process ( int r )
		{
			int t;
			int b;
			int k;
			int p;
			int n;
			int q;
			int m;

			p = _codec.NextIn;
			n = _codec.AvailableBytesIn;
			b = bitb;
			k = bitk;

			q = writeAt;
			m = ( int ) ( q < readAt ? readAt - q - 1 : end - q );

			while ( true )
			{
				switch ( mode )
				{
					case InflateBlockMode.TYPE:

						while ( k < ( 3 ) )
						{
							if ( n != 0 )
							{
								r = ZlibConstants.Z_OK;
							}
							else
							{
								bitb = b; bitk = k;
								_codec.AvailableBytesIn = n;
								_codec.TotalBytesIn += p - _codec.NextIn;
								_codec.NextIn = p;
								writeAt = q;
								return Flush ( r );
							}

							n--;
							b |= ( _codec.InputBuffer [ p++ ] & 0xff ) << k;
							k += 8;
						}
						t = ( int ) ( b & 7 );
						last = t & 1;

						switch ( ( uint ) t >> 1 )
						{
							case 0:
								b >>= 3; k -= ( 3 );
								t = k & 7;
								b >>= t; k -= t;
								mode = InflateBlockMode.LENS;
								break;

							case 1:
								int [] bl = new int [ 1 ];
								int [] bd = new int [ 1 ];
								int [] [] tl = new int [ 1 ] [];
								int [] [] td = new int [ 1 ] [];
								InfTree.inflate_trees_fixed ( bl, bd, tl, td, _codec );
								codes.Init ( bl [ 0 ], bd [ 0 ], tl [ 0 ], 0, td [ 0 ], 0 );
								b >>= 3; k -= 3;
								mode = InflateBlockMode.CODES;
								break;

							case 2:
								b >>= 3; k -= 3;
								mode = InflateBlockMode.TABLE;
								break;

							case 3:
								b >>= 3; k -= 3;
								mode = InflateBlockMode.BAD;
								_codec.Message = "invalid block type";
								r = ZlibConstants.Z_DATA_ERROR;
								bitb = b; bitk = k;
								_codec.AvailableBytesIn = n;
								_codec.TotalBytesIn += p - _codec.NextIn;
								_codec.NextIn = p;
								writeAt = q;
								return Flush ( r );
						}
						break;

					case InflateBlockMode.LENS:

						while ( k < ( 32 ) )
						{
							if ( n != 0 )
							{
								r = ZlibConstants.Z_OK;
							}
							else
							{
								bitb = b; bitk = k;
								_codec.AvailableBytesIn = n;
								_codec.TotalBytesIn += p - _codec.NextIn;
								_codec.NextIn = p;
								writeAt = q;
								return Flush ( r );
							}
							;
							n--;
							b |= ( _codec.InputBuffer [ p++ ] & 0xff ) << k;
							k += 8;
						}

						if ( ( ( ( ~b ) >> 16 ) & 0xffff ) != ( b & 0xffff ) )
						{
							mode = InflateBlockMode.BAD;
							_codec.Message = "invalid stored block lengths";
							r = ZlibConstants.Z_DATA_ERROR;

							bitb = b; bitk = k;
							_codec.AvailableBytesIn = n;
							_codec.TotalBytesIn += p - _codec.NextIn;
							_codec.NextIn = p;
							writeAt = q;
							return Flush ( r );
						}
						left = ( b & 0xffff );
						b = k = 0;
						mode = left != 0 ? InflateBlockMode.STORED : ( last != 0 ? InflateBlockMode.DRY : InflateBlockMode.TYPE );
						break;

					case InflateBlockMode.STORED:
						if ( n == 0 )
						{
							bitb = b; bitk = k;
							_codec.AvailableBytesIn = n;
							_codec.TotalBytesIn += p - _codec.NextIn;
							_codec.NextIn = p;
							writeAt = q;
							return Flush ( r );
						}

						if ( m == 0 )
						{
							if ( q == end && readAt != 0 )
							{
								q = 0; m = ( int ) ( q < readAt ? readAt - q - 1 : end - q );
							}
							if ( m == 0 )
							{
								writeAt = q;
								r = Flush ( r );
								q = writeAt; m = ( int ) ( q < readAt ? readAt - q - 1 : end - q );
								if ( q == end && readAt != 0 )
								{
									q = 0; m = ( int ) ( q < readAt ? readAt - q - 1 : end - q );
								}
								if ( m == 0 )
								{
									bitb = b; bitk = k;
									_codec.AvailableBytesIn = n;
									_codec.TotalBytesIn += p - _codec.NextIn;
									_codec.NextIn = p;
									writeAt = q;
									return Flush ( r );
								}
							}
						}
						r = ZlibConstants.Z_OK;

						t = left;
						if ( t > n )
							t = n;
						if ( t > m )
							t = m;
						Array.Copy ( _codec.InputBuffer, p, window, q, t );
						p += t; n -= t;
						q += t; m -= t;
						if ( ( left -= t ) != 0 )
							break;
						mode = last != 0 ? InflateBlockMode.DRY : InflateBlockMode.TYPE;
						break;

					case InflateBlockMode.TABLE:

						while ( k < ( 14 ) )
						{
							if ( n != 0 )
							{
								r = ZlibConstants.Z_OK;
							}
							else
							{
								bitb = b; bitk = k;
								_codec.AvailableBytesIn = n;
								_codec.TotalBytesIn += p - _codec.NextIn;
								_codec.NextIn = p;
								writeAt = q;
								return Flush ( r );
							}

							n--;
							b |= ( _codec.InputBuffer [ p++ ] & 0xff ) << k;
							k += 8;
						}

						table = t = ( b & 0x3fff );
						if ( ( t & 0x1f ) > 29 || ( ( t >> 5 ) & 0x1f ) > 29 )
						{
							mode = InflateBlockMode.BAD;
							_codec.Message = "too many length or distance symbols";
							r = ZlibConstants.Z_DATA_ERROR;

							bitb = b; bitk = k;
							_codec.AvailableBytesIn = n;
							_codec.TotalBytesIn += p - _codec.NextIn;
							_codec.NextIn = p;
							writeAt = q;
							return Flush ( r );
						}
						t = 258 + ( t & 0x1f ) + ( ( t >> 5 ) & 0x1f );
						if ( blens == null || blens.Length < t )
						{
							blens = new int [ t ];
						}
						else
						{
							Array.Clear ( blens, 0, t );
						}

						b >>= 14;
						k -= 14;


						index = 0;
						mode = InflateBlockMode.BTREE;
						goto case InflateBlockMode.BTREE;

					case InflateBlockMode.BTREE:
						while ( index < 4 + ( table >> 10 ) )
						{
							while ( k < ( 3 ) )
							{
								if ( n != 0 )
								{
									r = ZlibConstants.Z_OK;
								}
								else
								{
									bitb = b; bitk = k;
									_codec.AvailableBytesIn = n;
									_codec.TotalBytesIn += p - _codec.NextIn;
									_codec.NextIn = p;
									writeAt = q;
									return Flush ( r );
								}

								n--;
								b |= ( _codec.InputBuffer [ p++ ] & 0xff ) << k;
								k += 8;
							}

							blens [ border [ index++ ] ] = b & 7;

							b >>= 3; k -= 3;
						}

						while ( index < 19 )
						{
							blens [ border [ index++ ] ] = 0;
						}

						bb [ 0 ] = 7;
						t = inftree.inflate_trees_bits ( blens, bb, tb, hufts, _codec );
						if ( t != ZlibConstants.Z_OK )
						{
							r = t;
							if ( r == ZlibConstants.Z_DATA_ERROR )
							{
								blens = null;
								mode = InflateBlockMode.BAD;
							}

							bitb = b; bitk = k;
							_codec.AvailableBytesIn = n;
							_codec.TotalBytesIn += p - _codec.NextIn;
							_codec.NextIn = p;
							writeAt = q;
							return Flush ( r );
						}

						index = 0;
						mode = InflateBlockMode.DTREE;
						goto case InflateBlockMode.DTREE;

					case InflateBlockMode.DTREE:
						while ( true )
						{
							t = table;
							if ( !( index < 258 + ( t & 0x1f ) + ( ( t >> 5 ) & 0x1f ) ) )
							{
								break;
							}

							int i, j, c;

							t = bb [ 0 ];

							while ( k < t )
							{
								if ( n != 0 )
								{
									r = ZlibConstants.Z_OK;
								}
								else
								{
									bitb = b; bitk = k;
									_codec.AvailableBytesIn = n;
									_codec.TotalBytesIn += p - _codec.NextIn;
									_codec.NextIn = p;
									writeAt = q;
									return Flush ( r );
								}

								n--;
								b |= ( _codec.InputBuffer [ p++ ] & 0xff ) << k;
								k += 8;
							}

							t = hufts [ ( tb [ 0 ] + ( b & InternalInflateConstants.InflateMask [ t ] ) ) * 3 + 1 ];
							c = hufts [ ( tb [ 0 ] + ( b & InternalInflateConstants.InflateMask [ t ] ) ) * 3 + 2 ];

							if ( c < 16 )
							{
								b >>= t; k -= t;
								blens [ index++ ] = c;
							}
							else
							{
								i = c == 18 ? 7 : c - 14;
								j = c == 18 ? 11 : 3;

								while ( k < ( t + i ) )
								{
									if ( n != 0 )
									{
										r = ZlibConstants.Z_OK;
									}
									else
									{
										bitb = b; bitk = k;
										_codec.AvailableBytesIn = n;
										_codec.TotalBytesIn += p - _codec.NextIn;
										_codec.NextIn = p;
										writeAt = q;
										return Flush ( r );
									}

									n--;
									b |= ( _codec.InputBuffer [ p++ ] & 0xff ) << k;
									k += 8;
								}

								b >>= t; k -= t;

								j += ( b & InternalInflateConstants.InflateMask [ i ] );

								b >>= i; k -= i;

								i = index;
								t = table;
								if ( i + j > 258 + ( t & 0x1f ) + ( ( t >> 5 ) & 0x1f ) || ( c == 16 && i < 1 ) )
								{
									blens = null;
									mode = InflateBlockMode.BAD;
									_codec.Message = "invalid bit length repeat";
									r = ZlibConstants.Z_DATA_ERROR;

									bitb = b; bitk = k;
									_codec.AvailableBytesIn = n;
									_codec.TotalBytesIn += p - _codec.NextIn;
									_codec.NextIn = p;
									writeAt = q;
									return Flush ( r );
								}

								c = ( c == 16 ) ? blens [ i - 1 ] : 0;
								do
								{
									blens [ i++ ] = c;
								}
								while ( --j != 0 );
								index = i;
							}
						}

						tb [ 0 ] = -1;
						{
							int [] bl = new int [] { 9 };
							int [] bd = new int [] { 6 };
							int [] tl = new int [ 1 ];
							int [] td = new int [ 1 ];

							t = table;
							t = inftree.inflate_trees_dynamic ( 257 + ( t & 0x1f ), 1 + ( ( t >> 5 ) & 0x1f ), blens, bl, bd, tl, td, hufts, _codec );

							if ( t != ZlibConstants.Z_OK )
							{
								if ( t == ZlibConstants.Z_DATA_ERROR )
								{
									blens = null;
									mode = InflateBlockMode.BAD;
								}
								r = t;

								bitb = b; bitk = k;
								_codec.AvailableBytesIn = n;
								_codec.TotalBytesIn += p - _codec.NextIn;
								_codec.NextIn = p;
								writeAt = q;
								return Flush ( r );
							}
							codes.Init ( bl [ 0 ], bd [ 0 ], hufts, tl [ 0 ], hufts, td [ 0 ] );
						}
						mode = InflateBlockMode.CODES;
						goto case InflateBlockMode.CODES;

					case InflateBlockMode.CODES:
						bitb = b; bitk = k;
						_codec.AvailableBytesIn = n;
						_codec.TotalBytesIn += p - _codec.NextIn;
						_codec.NextIn = p;
						writeAt = q;

						r = codes.Process ( this, r );
						if ( r != ZlibConstants.Z_STREAM_END )
						{
							return Flush ( r );
						}

						r = ZlibConstants.Z_OK;
						p = _codec.NextIn;
						n = _codec.AvailableBytesIn;
						b = bitb;
						k = bitk;
						q = writeAt;
						m = ( int ) ( q < readAt ? readAt - q - 1 : end - q );

						if ( last == 0 )
						{
							mode = InflateBlockMode.TYPE;
							break;
						}
						mode = InflateBlockMode.DRY;
						goto case InflateBlockMode.DRY;

					case InflateBlockMode.DRY:
						writeAt = q;
						r = Flush ( r );
						q = writeAt; m = ( int ) ( q < readAt ? readAt - q - 1 : end - q );
						if ( readAt != writeAt )
						{
							bitb = b; bitk = k;
							_codec.AvailableBytesIn = n;
							_codec.TotalBytesIn += p - _codec.NextIn;
							_codec.NextIn = p;
							writeAt = q;
							return Flush ( r );
						}
						mode = InflateBlockMode.DONE;
						goto case InflateBlockMode.DONE;

					case InflateBlockMode.DONE:
						r = ZlibConstants.Z_STREAM_END;
						bitb = b;
						bitk = k;
						_codec.AvailableBytesIn = n;
						_codec.TotalBytesIn += p - _codec.NextIn;
						_codec.NextIn = p;
						writeAt = q;
						return Flush ( r );

					case InflateBlockMode.BAD:
						r = ZlibConstants.Z_DATA_ERROR;

						bitb = b; bitk = k;
						_codec.AvailableBytesIn = n;
						_codec.TotalBytesIn += p - _codec.NextIn;
						_codec.NextIn = p;
						writeAt = q;
						return Flush ( r );


					default:
						r = ZlibConstants.Z_STREAM_ERROR;

						bitb = b; bitk = k;
						_codec.AvailableBytesIn = n;
						_codec.TotalBytesIn += p - _codec.NextIn;
						_codec.NextIn = p;
						writeAt = q;
						return Flush ( r );
				}
			}
		}


		internal void Free ()
		{
			Reset ();
			window = null;
			hufts = null;
		}

		internal void SetDictionary ( byte [] d, int start, int n )
		{
			Array.Copy ( d, start, window, 0, n );
			readAt = writeAt = n;
		}

		internal int SyncPoint ()
		{
			return mode == InflateBlockMode.LENS ? 1 : 0;
		}

		internal int Flush ( int r )
		{
			int nBytes;

			for ( int pass = 0; pass < 2; pass++ )
			{
				if ( pass == 0 )
				{
					nBytes = ( int ) ( ( readAt <= writeAt ? writeAt : end ) - readAt );
				}
				else
				{
					nBytes = writeAt - readAt;
				}

				if ( nBytes == 0 )
				{
					if ( r == ZlibConstants.Z_BUF_ERROR )
						r = ZlibConstants.Z_OK;
					return r;
				}

				if ( nBytes > _codec.AvailableBytesOut )
					nBytes = _codec.AvailableBytesOut;

				if ( nBytes != 0 && r == ZlibConstants.Z_BUF_ERROR )
					r = ZlibConstants.Z_OK;

				_codec.AvailableBytesOut -= nBytes;
				_codec.TotalBytesOut += nBytes;

				if ( checkfn != null )
					_codec.adler32 = check = Adler.Adler32 ( check, window, readAt, nBytes );

				Array.Copy ( window, readAt, _codec.OutputBuffer, _codec.NextOut, nBytes );
				_codec.NextOut += nBytes;
				readAt += nBytes;

				if ( readAt == end && pass == 0 )
				{
					readAt = 0;
					if ( writeAt == end )
						writeAt = 0;
				}
				else pass++;
			}

			return r;
		}
	}


	internal static class InternalInflateConstants
	{
		internal static readonly int [] InflateMask = new int [] {
            0x00000000, 0x00000001, 0x00000003, 0x00000007,
            0x0000000f, 0x0000001f, 0x0000003f, 0x0000007f,
            0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff,
            0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff };
	}


	sealed class InflateCodes
	{
		private const int START = 0;
		private const int LEN = 1;
		private const int LENEXT = 2;
		private const int DIST = 3;
		private const int DISTEXT = 4;
		private const int COPY = 5;
		private const int LIT = 6;
		private const int WASH = 7;
		private const int END = 8;
		private const int BADCODE = 9;

		internal int mode;

		internal int len;

		internal int [] tree;
		internal int tree_index = 0;
		internal int need;

		internal int lit;

		internal int bitsToGet;
		internal int dist;

		internal byte lbits;
		internal byte dbits;
		internal int [] ltree;
		internal int ltree_index;
		internal int [] dtree;
		internal int dtree_index;

		internal InflateCodes ()
		{
		}

		internal void Init ( int bl, int bd, int [] tl, int tl_index, int [] td, int td_index )
		{
			mode = START;
			lbits = ( byte ) bl;
			dbits = ( byte ) bd;
			ltree = tl;
			ltree_index = tl_index;
			dtree = td;
			dtree_index = td_index;
			tree = null;
		}

		internal int Process ( InflateBlocks blocks, int r )
		{
			int j;
			int tindex;
			int e;
			int b = 0;
			int k = 0;
			int p = 0;
			int n;
			int q;
			int m;
			int f;

			ZlibCodec z = blocks._codec;

			p = z.NextIn;
			n = z.AvailableBytesIn;
			b = blocks.bitb;
			k = blocks.bitk;
			q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;

			while ( true )
			{
				switch ( mode )
				{
					case START:
						if ( m >= 258 && n >= 10 )
						{
							blocks.bitb = b; blocks.bitk = k;
							z.AvailableBytesIn = n;
							z.TotalBytesIn += p - z.NextIn;
							z.NextIn = p;
							blocks.writeAt = q;
							r = InflateFast ( lbits, dbits, ltree, ltree_index, dtree, dtree_index, blocks, z );

							p = z.NextIn;
							n = z.AvailableBytesIn;
							b = blocks.bitb;
							k = blocks.bitk;
							q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;

							if ( r != ZlibConstants.Z_OK )
							{
								mode = ( r == ZlibConstants.Z_STREAM_END ) ? WASH : BADCODE;
								break;
							}
						}
						need = lbits;
						tree = ltree;
						tree_index = ltree_index;

						mode = LEN;
						goto case LEN;

					case LEN:
						j = need;

						while ( k < j )
						{
							if ( n != 0 )
								r = ZlibConstants.Z_OK;
							else
							{
								blocks.bitb = b; blocks.bitk = k;
								z.AvailableBytesIn = n;
								z.TotalBytesIn += p - z.NextIn;
								z.NextIn = p;
								blocks.writeAt = q;
								return blocks.Flush ( r );
							}
							n--;
							b |= ( z.InputBuffer [ p++ ] & 0xff ) << k;
							k += 8;
						}

						tindex = ( tree_index + ( b & InternalInflateConstants.InflateMask [ j ] ) ) * 3;

						b >>= ( tree [ tindex + 1 ] );
						k -= ( tree [ tindex + 1 ] );

						e = tree [ tindex ];

						if ( e == 0 )
						{
							lit = tree [ tindex + 2 ];
							mode = LIT;
							break;
						}
						if ( ( e & 16 ) != 0 )
						{
							bitsToGet = e & 15;
							len = tree [ tindex + 2 ];
							mode = LENEXT;
							break;
						}
						if ( ( e & 64 ) == 0 )
						{
							need = e;
							tree_index = tindex / 3 + tree [ tindex + 2 ];
							break;
						}
						if ( ( e & 32 ) != 0 )
						{
							mode = WASH;
							break;
						}
						mode = BADCODE;
						z.Message = "invalid literal/length code";
						r = ZlibConstants.Z_DATA_ERROR;

						blocks.bitb = b; blocks.bitk = k;
						z.AvailableBytesIn = n;
						z.TotalBytesIn += p - z.NextIn;
						z.NextIn = p;
						blocks.writeAt = q;
						return blocks.Flush ( r );

					case LENEXT:
						j = bitsToGet;

						while ( k < j )
						{
							if ( n != 0 )
								r = ZlibConstants.Z_OK;
							else
							{
								blocks.bitb = b; blocks.bitk = k;
								z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
								blocks.writeAt = q;
								return blocks.Flush ( r );
							}
							n--; b |= ( z.InputBuffer [ p++ ] & 0xff ) << k;
							k += 8;
						}

						len += ( b & InternalInflateConstants.InflateMask [ j ] );

						b >>= j;
						k -= j;

						need = dbits;
						tree = dtree;
						tree_index = dtree_index;
						mode = DIST;
						goto case DIST;

					case DIST:
						j = need;

						while ( k < j )
						{
							if ( n != 0 )
								r = ZlibConstants.Z_OK;
							else
							{
								blocks.bitb = b; blocks.bitk = k;
								z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
								blocks.writeAt = q;
								return blocks.Flush ( r );
							}
							n--; b |= ( z.InputBuffer [ p++ ] & 0xff ) << k;
							k += 8;
						}

						tindex = ( tree_index + ( b & InternalInflateConstants.InflateMask [ j ] ) ) * 3;

						b >>= tree [ tindex + 1 ];
						k -= tree [ tindex + 1 ];

						e = ( tree [ tindex ] );
						if ( ( e & 0x10 ) != 0 )
						{
							bitsToGet = e & 15;
							dist = tree [ tindex + 2 ];
							mode = DISTEXT;
							break;
						}
						if ( ( e & 64 ) == 0 )
						{
							need = e;
							tree_index = tindex / 3 + tree [ tindex + 2 ];
							break;
						}
						mode = BADCODE;
						z.Message = "invalid distance code";
						r = ZlibConstants.Z_DATA_ERROR;

						blocks.bitb = b; blocks.bitk = k;
						z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
						blocks.writeAt = q;
						return blocks.Flush ( r );

					case DISTEXT:
						j = bitsToGet;

						while ( k < j )
						{
							if ( n != 0 )
								r = ZlibConstants.Z_OK;
							else
							{
								blocks.bitb = b; blocks.bitk = k;
								z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
								blocks.writeAt = q;
								return blocks.Flush ( r );
							}
							n--; b |= ( z.InputBuffer [ p++ ] & 0xff ) << k;
							k += 8;
						}

						dist += ( b & InternalInflateConstants.InflateMask [ j ] );

						b >>= j;
						k -= j;

						mode = COPY;
						goto case COPY;

					case COPY:
						f = q - dist;
						while ( f < 0 )
						{
							f += blocks.end;
						}
						while ( len != 0 )
						{
							if ( m == 0 )
							{
								if ( q == blocks.end && blocks.readAt != 0 )
								{
									q = 0; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;
								}
								if ( m == 0 )
								{
									blocks.writeAt = q; r = blocks.Flush ( r );
									q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;

									if ( q == blocks.end && blocks.readAt != 0 )
									{
										q = 0; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;
									}

									if ( m == 0 )
									{
										blocks.bitb = b; blocks.bitk = k;
										z.AvailableBytesIn = n;
										z.TotalBytesIn += p - z.NextIn;
										z.NextIn = p;
										blocks.writeAt = q;
										return blocks.Flush ( r );
									}
								}
							}

							blocks.window [ q++ ] = blocks.window [ f++ ]; m--;

							if ( f == blocks.end )
								f = 0;
							len--;
						}
						mode = START;
						break;

					case LIT:
						if ( m == 0 )
						{
							if ( q == blocks.end && blocks.readAt != 0 )
							{
								q = 0; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;
							}
							if ( m == 0 )
							{
								blocks.writeAt = q; r = blocks.Flush ( r );
								q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;

								if ( q == blocks.end && blocks.readAt != 0 )
								{
									q = 0; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;
								}
								if ( m == 0 )
								{
									blocks.bitb = b; blocks.bitk = k;
									z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
									blocks.writeAt = q;
									return blocks.Flush ( r );
								}
							}
						}
						r = ZlibConstants.Z_OK;

						blocks.window [ q++ ] = ( byte ) lit; m--;

						mode = START;
						break;

					case WASH:
						if ( k > 7 )
						{
							k -= 8;
							n++;
							p--;
						}

						blocks.writeAt = q; r = blocks.Flush ( r );
						q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q;

						if ( blocks.readAt != blocks.writeAt )
						{
							blocks.bitb = b; blocks.bitk = k;
							z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
							blocks.writeAt = q;
							return blocks.Flush ( r );
						}
						mode = END;
						goto case END;

					case END:
						r = ZlibConstants.Z_STREAM_END;
						blocks.bitb = b; blocks.bitk = k;
						z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
						blocks.writeAt = q;
						return blocks.Flush ( r );

					case BADCODE:

						r = ZlibConstants.Z_DATA_ERROR;

						blocks.bitb = b; blocks.bitk = k;
						z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
						blocks.writeAt = q;
						return blocks.Flush ( r );

					default:
						r = ZlibConstants.Z_STREAM_ERROR;

						blocks.bitb = b; blocks.bitk = k;
						z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
						blocks.writeAt = q;
						return blocks.Flush ( r );
				}
			}
		}

		internal int InflateFast ( int bl, int bd, int [] tl, int tl_index, int [] td, int td_index, InflateBlocks s, ZlibCodec z )
		{
			int t;
			int [] tp;
			int tp_index;
			int e;
			int b;
			int k;
			int p;
			int n;
			int q;
			int m;
			int ml;
			int md;
			int c;
			int d;
			int r;

			int tp_index_t_3;

			p = z.NextIn; n = z.AvailableBytesIn; b = s.bitb; k = s.bitk;
			q = s.writeAt; m = q < s.readAt ? s.readAt - q - 1 : s.end - q;

			ml = InternalInflateConstants.InflateMask [ bl ];
			md = InternalInflateConstants.InflateMask [ bd ];

			do
			{
				while ( k < ( 20 ) )
				{
					n--;
					b |= ( z.InputBuffer [ p++ ] & 0xff ) << k; k += 8;
				}

				t = b & ml;
				tp = tl;
				tp_index = tl_index;
				tp_index_t_3 = ( tp_index + t ) * 3;
				if ( ( e = tp [ tp_index_t_3 ] ) == 0 )
				{
					b >>= ( tp [ tp_index_t_3 + 1 ] ); k -= ( tp [ tp_index_t_3 + 1 ] );

					s.window [ q++ ] = ( byte ) tp [ tp_index_t_3 + 2 ];
					m--;
					continue;
				}
				do
				{

					b >>= ( tp [ tp_index_t_3 + 1 ] ); k -= ( tp [ tp_index_t_3 + 1 ] );

					if ( ( e & 16 ) != 0 )
					{
						e &= 15;
						c = tp [ tp_index_t_3 + 2 ] + ( ( int ) b & InternalInflateConstants.InflateMask [ e ] );

						b >>= e; k -= e;

						while ( k < 15 )
						{
							n--;
							b |= ( z.InputBuffer [ p++ ] & 0xff ) << k; k += 8;
						}

						t = b & md;
						tp = td;
						tp_index = td_index;
						tp_index_t_3 = ( tp_index + t ) * 3;
						e = tp [ tp_index_t_3 ];

						do
						{

							b >>= ( tp [ tp_index_t_3 + 1 ] ); k -= ( tp [ tp_index_t_3 + 1 ] );

							if ( ( e & 16 ) != 0 )
							{
								e &= 15;
								while ( k < e )
								{
									n--;
									b |= ( z.InputBuffer [ p++ ] & 0xff ) << k; k += 8;
								}

								d = tp [ tp_index_t_3 + 2 ] + ( b & InternalInflateConstants.InflateMask [ e ] );

								b >>= e; k -= e;

								m -= c;
								if ( q >= d )
								{
									r = q - d;
									if ( q - r > 0 && 2 > ( q - r ) )
									{
										s.window [ q++ ] = s.window [ r++ ];
										s.window [ q++ ] = s.window [ r++ ];
										c -= 2;
									}
									else
									{
										Array.Copy ( s.window, r, s.window, q, 2 );
										q += 2; r += 2; c -= 2;
									}
								}
								else
								{
									r = q - d;
									do
									{
										r += s.end;
									}
									while ( r < 0 );
									e = s.end - r;
									if ( c > e )
									{
										c -= e;
										if ( q - r > 0 && e > ( q - r ) )
										{
											do
											{
												s.window [ q++ ] = s.window [ r++ ];
											}
											while ( --e != 0 );
										}
										else
										{
											Array.Copy ( s.window, r, s.window, q, e );
											q += e; r += e; e = 0;
										}
										r = 0;
									}
								}

								if ( q - r > 0 && c > ( q - r ) )
								{
									do
									{
										s.window [ q++ ] = s.window [ r++ ];
									}
									while ( --c != 0 );
								}
								else
								{
									Array.Copy ( s.window, r, s.window, q, c );
									q += c; r += c; c = 0;
								}
								break;
							}
							else if ( ( e & 64 ) == 0 )
							{
								t += tp [ tp_index_t_3 + 2 ];
								t += ( b & InternalInflateConstants.InflateMask [ e ] );
								tp_index_t_3 = ( tp_index + t ) * 3;
								e = tp [ tp_index_t_3 ];
							}
							else
							{
								z.Message = "invalid distance code";

								c = z.AvailableBytesIn - n; c = ( k >> 3 ) < c ? k >> 3 : c; n += c; p -= c; k -= ( c << 3 );

								s.bitb = b; s.bitk = k;
								z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
								s.writeAt = q;

								return ZlibConstants.Z_DATA_ERROR;
							}
						}
						while ( true );
						break;
					}

					if ( ( e & 64 ) == 0 )
					{
						t += tp [ tp_index_t_3 + 2 ];
						t += ( b & InternalInflateConstants.InflateMask [ e ] );
						tp_index_t_3 = ( tp_index + t ) * 3;
						if ( ( e = tp [ tp_index_t_3 ] ) == 0 )
						{
							b >>= ( tp [ tp_index_t_3 + 1 ] ); k -= ( tp [ tp_index_t_3 + 1 ] );
							s.window [ q++ ] = ( byte ) tp [ tp_index_t_3 + 2 ];
							m--;
							break;
						}
					}
					else if ( ( e & 32 ) != 0 )
					{
						c = z.AvailableBytesIn - n; c = ( k >> 3 ) < c ? k >> 3 : c; n += c; p -= c; k -= ( c << 3 );

						s.bitb = b; s.bitk = k;
						z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
						s.writeAt = q;

						return ZlibConstants.Z_STREAM_END;
					}
					else
					{
						z.Message = "invalid literal/length code";

						c = z.AvailableBytesIn - n; c = ( k >> 3 ) < c ? k >> 3 : c; n += c; p -= c; k -= ( c << 3 );

						s.bitb = b; s.bitk = k;
						z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
						s.writeAt = q;

						return ZlibConstants.Z_DATA_ERROR;
					}
				}
				while ( true );
			}
			while ( m >= 258 && n >= 10 );

			c = z.AvailableBytesIn - n; c = ( k >> 3 ) < c ? k >> 3 : c; n += c; p -= c; k -= ( c << 3 );

			s.bitb = b; s.bitk = k;
			z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p;
			s.writeAt = q;

			return ZlibConstants.Z_OK;
		}
	}


	internal sealed class InflateManager
	{
		private const int PRESET_DICT = 0x20;

		private const int Z_DEFLATED = 8;

		private enum InflateManagerMode
		{
			METHOD = 0,
			FLAG = 1,
			DICT4 = 2,
			DICT3 = 3,
			DICT2 = 4,
			DICT1 = 5,
			DICT0 = 6,
			BLOCKS = 7,
			CHECK4 = 8,
			CHECK3 = 9,
			CHECK2 = 10,
			CHECK1 = 11,
			DONE = 12,
			BAD = 13,
		}

		private InflateManagerMode mode;
		internal ZlibCodec _codec;

		internal int method;

		internal uint computedCheck;
		internal uint expectedCheck;

		internal int marker;

		private bool _handleRfc1950HeaderBytes = true;
		internal bool HandleRfc1950HeaderBytes
		{
			get { return _handleRfc1950HeaderBytes; }
			set { _handleRfc1950HeaderBytes = value; }
		}
		internal int wbits;

		internal InflateBlocks blocks;

		public InflateManager () { }

		public InflateManager ( bool expectRfc1950HeaderBytes )
		{
			_handleRfc1950HeaderBytes = expectRfc1950HeaderBytes;
		}

		internal int Reset ()
		{
			_codec.TotalBytesIn = _codec.TotalBytesOut = 0;
			_codec.Message = null;
			mode = HandleRfc1950HeaderBytes ? InflateManagerMode.METHOD : InflateManagerMode.BLOCKS;
			blocks.Reset ();
			return ZlibConstants.Z_OK;
		}

		internal int End ()
		{
			if ( blocks != null )
				blocks.Free ();
			blocks = null;
			return ZlibConstants.Z_OK;
		}

		internal int Initialize ( ZlibCodec codec, int w )
		{
			_codec = codec;
			_codec.Message = null;
			blocks = null;

			if ( w < 8 || w > 15 )
			{
				End ();
				throw new CompressionProcessException ( "Bad window size." );
			}
			wbits = w;

			blocks = new InflateBlocks ( codec,
				HandleRfc1950HeaderBytes ? this : null,
				1 << w );

			Reset ();
			return ZlibConstants.Z_OK;
		}


		internal int Inflate ( FlushType flush )
		{
			int b;

			if ( _codec.InputBuffer == null )
				throw new CompressionProcessException ( "InputBuffer is null. " );

			int f = ZlibConstants.Z_OK;
			int r = ZlibConstants.Z_BUF_ERROR;

			while ( true )
			{
				switch ( mode )
				{
					case InflateManagerMode.METHOD:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--;
						_codec.TotalBytesIn++;
						if ( ( ( method = _codec.InputBuffer [ _codec.NextIn++ ] ) & 0xf ) != Z_DEFLATED )
						{
							mode = InflateManagerMode.BAD;
							_codec.Message = String.Format ( "unknown compression method (0x{0:X2})", method );
							marker = 5;
							break;
						}
						if ( ( method >> 4 ) + 8 > wbits )
						{
							mode = InflateManagerMode.BAD;
							_codec.Message = String.Format ( "invalid window size ({0})", ( method >> 4 ) + 8 );
							marker = 5;
							break;
						}
						mode = InflateManagerMode.FLAG;
						break;

					case InflateManagerMode.FLAG:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--;
						_codec.TotalBytesIn++;
						b = ( _codec.InputBuffer [ _codec.NextIn++ ] ) & 0xff;

						if ( ( ( ( method << 8 ) + b ) % 31 ) != 0 )
						{
							mode = InflateManagerMode.BAD;
							_codec.Message = "incorrect header check";
							marker = 5;
							break;
						}

						mode = ( ( b & PRESET_DICT ) == 0 )
							? InflateManagerMode.BLOCKS
							: InflateManagerMode.DICT4;
						break;

					case InflateManagerMode.DICT4:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--;
						_codec.TotalBytesIn++;
						expectedCheck = ( uint ) ( ( _codec.InputBuffer [ _codec.NextIn++ ] << 24 ) & 0xff000000 );
						mode = InflateManagerMode.DICT3;
						break;

					case InflateManagerMode.DICT3:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--;
						_codec.TotalBytesIn++;
						expectedCheck += ( uint ) ( ( _codec.InputBuffer [ _codec.NextIn++ ] << 16 ) & 0x00ff0000 );
						mode = InflateManagerMode.DICT2;
						break;

					case InflateManagerMode.DICT2:

						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--;
						_codec.TotalBytesIn++;
						expectedCheck += ( uint ) ( ( _codec.InputBuffer [ _codec.NextIn++ ] << 8 ) & 0x0000ff00 );
						mode = InflateManagerMode.DICT1;
						break;

					case InflateManagerMode.DICT1:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
						expectedCheck += ( uint ) ( _codec.InputBuffer [ _codec.NextIn++ ] & 0x000000ff );
						_codec.adler32 = expectedCheck;
						mode = InflateManagerMode.DICT0;
						return ZlibConstants.Z_NEED_DICT;

					case InflateManagerMode.DICT0:
						mode = InflateManagerMode.BAD;
						_codec.Message = "need dictionary";
						marker = 0;
						return ZlibConstants.Z_STREAM_ERROR;

					case InflateManagerMode.BLOCKS:
						r = blocks.Process ( r );
						if ( r == ZlibConstants.Z_DATA_ERROR )
						{
							mode = InflateManagerMode.BAD;
							marker = 0;
							break;
						}

						if ( r == ZlibConstants.Z_OK ) r = f;

						if ( r != ZlibConstants.Z_STREAM_END )
							return r;

						r = f;
						computedCheck = blocks.Reset ();
						if ( !HandleRfc1950HeaderBytes )
						{
							mode = InflateManagerMode.DONE;
							return ZlibConstants.Z_STREAM_END;
						}
						mode = InflateManagerMode.CHECK4;
						break;

					case InflateManagerMode.CHECK4:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--;
						_codec.TotalBytesIn++;
						expectedCheck = ( uint ) ( ( _codec.InputBuffer [ _codec.NextIn++ ] << 24 ) & 0xff000000 );
						mode = InflateManagerMode.CHECK3;
						break;

					case InflateManagerMode.CHECK3:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
						expectedCheck += ( uint ) ( ( _codec.InputBuffer [ _codec.NextIn++ ] << 16 ) & 0x00ff0000 );
						mode = InflateManagerMode.CHECK2;
						break;

					case InflateManagerMode.CHECK2:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--;
						_codec.TotalBytesIn++;
						expectedCheck += ( uint ) ( ( _codec.InputBuffer [ _codec.NextIn++ ] << 8 ) & 0x0000ff00 );
						mode = InflateManagerMode.CHECK1;
						break;

					case InflateManagerMode.CHECK1:
						if ( _codec.AvailableBytesIn == 0 ) return r;
						r = f;
						_codec.AvailableBytesIn--; _codec.TotalBytesIn++;
						expectedCheck += ( uint ) ( _codec.InputBuffer [ _codec.NextIn++ ] & 0x000000ff );
						if ( computedCheck != expectedCheck )
						{
							mode = InflateManagerMode.BAD;
							_codec.Message = "incorrect data check";
							marker = 5;
							break;
						}
						mode = InflateManagerMode.DONE;
						return ZlibConstants.Z_STREAM_END;

					case InflateManagerMode.DONE:
						return ZlibConstants.Z_STREAM_END;

					case InflateManagerMode.BAD:
						throw new CompressionProcessException ( String.Format ( "Bad state ({0})", _codec.Message ) );

					default:
						throw new CompressionProcessException ( "Stream error." );
				}
			}
		}

		internal int SetDictionary ( byte [] dictionary )
		{
			int index = 0;
			int length = dictionary.Length;
			if ( mode != InflateManagerMode.DICT0 )
				throw new CompressionProcessException ( "Stream error." );

			if ( Adler.Adler32 ( 1, dictionary, 0, dictionary.Length ) != _codec.adler32 )
			{
				return ZlibConstants.Z_DATA_ERROR;
			}

			_codec.adler32 = Adler.Adler32 ( 0, null, 0, 0 );

			if ( length >= ( 1 << wbits ) )
			{
				length = ( 1 << wbits ) - 1;
				index = dictionary.Length - length;
			}
			blocks.SetDictionary ( dictionary, index, length );
			mode = InflateManagerMode.BLOCKS;
			return ZlibConstants.Z_OK;
		}


		private static readonly byte [] mark = new byte [] { 0, 0, 0xff, 0xff };

		internal int Sync ()
		{
			int n;
			int p;
			int m;
			long r, w;

			if ( mode != InflateManagerMode.BAD )
			{
				mode = InflateManagerMode.BAD;
				marker = 0;
			}
			if ( ( n = _codec.AvailableBytesIn ) == 0 )
				return ZlibConstants.Z_BUF_ERROR;
			p = _codec.NextIn;
			m = marker;

			while ( n != 0 && m < 4 )
			{
				if ( _codec.InputBuffer [ p ] == mark [ m ] )
				{
					m++;
				}
				else if ( _codec.InputBuffer [ p ] != 0 )
				{
					m = 0;
				}
				else
				{
					m = 4 - m;
				}
				p++; n--;
			}

			_codec.TotalBytesIn += p - _codec.NextIn;
			_codec.NextIn = p;
			_codec.AvailableBytesIn = n;
			marker = m;

			if ( m != 4 )
			{
				return ZlibConstants.Z_DATA_ERROR;
			}
			r = _codec.TotalBytesIn;
			w = _codec.TotalBytesOut;
			Reset ();
			_codec.TotalBytesIn = r;
			_codec.TotalBytesOut = w;
			mode = InflateManagerMode.BLOCKS;
			return ZlibConstants.Z_OK;
		}

		internal int SyncPoint ( ZlibCodec z )
		{
			return blocks.SyncPoint ();
		}
	}
}
